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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 640 (Engine Controls Diagnosis - 3.6L (Ly7) (DTC P2228 - DTC P2626)) >> Diagnostic Trouble Codes >> DTC P2228 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  This step determines if a condition exists.
  2. 4:  This step is testing the signal circuit. The signal circuit is pulled-up to a voltage, so the DMM should display a voltage within the specified range. If the voltage is low, this indicates the signal circuit is grounded.
  3. 5:  The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the BARO sensor. If the amperage on the 5-volt reference circuit is less than the specified value, test the 5-volt reference circuit for an open, a high resistance, or for a short to ground.
DTC P2228

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Control Module (ECM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Clear the diagnostic trouble codes (DTCs) with a scan tool.
  3. Start the engine.
  4. Observe the DTC information with a scan tool.
Does the DTC fail this ignition?		 - Go to Step 4  Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn OFF the ignition.
  2. Disconnect the barometric pressure (BARO) sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the signal circuit of the BARO sensor and the engine control module (ECM) housing with a DMM.
Is the voltage within the specified range?		 5.2-6.2 V Go to Step 5  Go to Step 7 
5 
  1. Set-up a DMM to test amperage on the 400 mA scale.
  2. Measure the amperage between the 5-volt reference circuit of the BARO sensor and the ECM housing with a DMM.
Is the amperage more than the specified value?		 80 mA Go to Step 8  Go to Step 6 
6
  1. Turn OFF the ignition.
    2. IMPORTANT: The 5-volt reference circuits are internally connected within the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.
  2. Test the 5-volt reference circuit of the BARO sensor and all shared 5-volt reference circuits for the following:
    • An open
    • A short to ground
    • High resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
7 Test the signal circuit of the BARO sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
8 Test for an intermittent and for a poor connection at the BARO sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 10 
9 Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
10 Replace the BARO sensor. Refer to Barometric Pressure (BARO) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 12  -
11 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 12  -
12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 13 
13 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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